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        검색결과 4

        1.
        2017.12 구독 인증기관 무료, 개인회원 유료
        With the rapid development of the global economy, transport safety and security have become the key issues in maritime transportation all over the world. In practical applications, the Automatic Identification System (AIS)-based measurement of similarities between different vessel trajectories plays an important role in improving maritime transportation, e.g., maritime navigation, maritime supervision and management. However, the received AIS datasets are usually composed of a large amount of redundant information which could significantly increase the computational complexity. To deal with this problem, a Douglas-Peucker (DP)-based calculation method is introduced in this paper to accurately compress the spatio-temporal AIS trajectories while preserving the main geometrical structures. Based on the compressed trajectories, it is able to accelerate the Dynamic Time Warping (DTW) algorithm for the measurement of similarities between different vessel trajectories. In particular, the combination of DP and DTW has the capacity of significantly reducing the computational cost and guaranteeing the accuracy of similarity measures. The experimental results have demonstrated the superior performance of the proposed method in terms of computational cost and accuracy of similarity measures.
        4,000원
        2.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Isotactic polyacrylonitrile (PAN) with triad isotacticity of 0.53, which was determined by 13C NMR, using dialkylmagnesium as an initiator, was successfully synthesized. Isothermal treatment of iso-PAN was conducted in air at 200, 220, 250 and 280℃. Structural evolutions and chemical changes were studied with Fourier transformation infrared and wide-angle X-ray diffraction during stabilization. A new parameter CNF=I2240cm-1/ (I1595cm-1+f*I1595cm-1) was defined to evaluate residual nitrile groups. Crystallinity and crystal size were calculated with X-ray diffraction dates. The results indicated that the nitrile groups had partly converted into a ladder structure as stabilization proceeded. The rate of reaction increased with treatment temperature; crystallinity and crystal size decreased proportionally to pyrolysis temperature. The iso-conversional method coupled with the Kissinger and Flynn-Wall-Ozawa methods were used to determine kinetic parameters via differential scanning calorimetry analysis with different heating rates. The active energy of the reaction was 171.1 and 169.1 kJ/mol, calculated with the two methods respectively and implied the sensitivity of the reaction with temperature.
        4,000원
        3.
        2009.08 구독 인증기관·개인회원 무료
        A total of 106 two month-old Nanjiang yellow goats (male were 32, female were 34 and castrated were 40) were divided into treatment group and control group to determine the growth performance. The treatment group was reared in grazing mode, experimental group was pastured with supplement feeding. The results showed that the body weight of male in experiment group was heavier by 9.82%(P<0.05), 11.87%(P<0.01), 16.91%(P<0.01) and 23.99%(P<0.05) than that in control group in 3,4,5 and 6 month-age. The body weight of female in experimental group was heavier by 11.54%(P<0.05), 13.79%(P<0.01), 17.47%(P<0.01) and 21.15%(P<0.01) than that in control group in 3,4,5 and 6 month-old. The body weight of castrator in experimental group was heavier by 1.58%, 1.99%, 13.08%(P<0.01) and 15.76%(P<0.01) than that in control group in 3,4,5 and 6 month-age. The daily increasing weight and body measurements of experimental group is improved more than control group, especially in 6 month-age.